I have two websites I am currently working on/have completed in the past that I'm trying to move from desktop sites, to mobile friendly design, and I'm struggling on how, and where to start, or where I am doing things wrong with sizing my elements as I've been told multiple different things. (specifically with 'sections/containers' I've been told to use rems, use %s, use vh, vw, for setting heights/widths and frequently run into issues with using those and getting different effects on smaller screens) and its been causing a significant amount of anxiety, and mental turmoil / imposer syndrome and self doubt.